Chain saw



FIG. 1 is a perspective view of a top, front and left side of the chain saw incorporating my new design;

FIG. 2 is a perspective view of the top, rear and right side thereof;

FIG. 3 is a top plan view thereof;

FIG. 4 is a left side elevational view thereof;

FIG. 5 is a front elevational view thereof;

FIG. 6 is a rear elevational view thereof;

FIG. 7 is a right side elevational view thereof; and,

FIG. 8 is a bottom plan view thereof. 

I claim the ornamental design for a chain saw, as shown and described. 